JPH06113222A - Picture character data arithmetic operation unit - Google Patents

Abstract

PURPOSE:To display an easy to see character on a screen by interpolating data of one line based on data by two(preceding and succeeding) lines so as to smooth a contour of a character. CONSTITUTION:Data of (m+1)th line are stored in a line memory 34 and data of m-th line are stored in a line memory 36. Each memory adopts FIFO configuration. When data of the two lines are prepared, a write/read SW 38 accesses the memories 34,36, the read character data are sent to a data arithmetic operation section 40, in which red, green, blue colors forming character information are calculated. In this case, data by one line between the two lines are generated through interpolation in the unit of dots based on the character information read from each memory and the result is synthesized with an external video signal 24 with an NTSC encoder. As a result, ruggedness having been observed in the contour of the character is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image character data calculation device for displaying desired character information by superimposing it on a video signal output to a television monitor.

[0002]

2. Description of the Related Art Conventionally, an image processing apparatus for superimposing and displaying desired character information on a video signal output to a television monitor has a configuration as shown in FIG. Here, it is assumed that the display character information is composed of the three primary colors of light of red, green, and blue as color data, but the same structure except that the structure of display data is different even for monochrome character data. Take The field memory 2 generates and stores character information composed of a collection of dots. The field memory described here has half the capacity of one display screen. As can be seen from FIG. 3, in the interlaced scanning system, one screen is generally defined as 2 fields = 1 frame, such that the scanning lines shown by dotted lines are odd fields and the scanning lines shown by solid lines are even fields.
A video signal from the outside is input to the sync separation circuit 6 and the encoder 8 via the interface 4.

In the sync separation circuit 6, the external video signal 2
The horizontal synchronizing signal and the vertical synchronizing signal included in 4 are separated from each other. The separated sync signal 12 is input to the memory controller 10. The memory controller 10 controls the reading of the field memory 2 by a control signal 1
4 and an external video signal 24, a clock signal 16 is generated for synchronization with the control signal 14 to the field memory 2 and the clock signal 16 to the digital-analog converter 1.
8 are supplied.

The display character data is read out as a digital signal 22 in synchronization with the control signal 14 output from the memory controller 10, and the digital signal 22 is synchronized with the clock signal 16 by the digital-analog converter 18 to generate an analog R signal.
It is converted into a GB signal 20 and input to the encoder 8. The encoder 8 uses the external video signal 24 and analog RGB signals.
After the signal 20 is synthesized and converted into the NTSC signal 26, T
Output to the V monitor 28.

With the above operation, the arrival of the vertical synchronizing signal contained in the external video signal 24 is detected, and a series of display operations for each screen is repeated.

[0006]

However, as can be seen from FIG. 6, the minimum unit of the character information is a dot, so that the outline of the character in the oblique direction is stepwise on the display screen depending on the character. You can see that Further, since the field memory 2 for display characters has only one field, the same character data is output in both the odd and even fields, so that the same data is displayed in units of two lines as shown in FIG. Therefore, the displayed characters are disadvantageous in that they are not good in appearance because of the fact that the outline of the characters is stepwise in the vertical direction. The problem of resolution in the vertical direction is solved by allocating field memories for odd / even fields, respectively, but the cost is increased because the memory capacity is doubled.

The present invention has been made to solve the above-mentioned problems, and when character information composed of dots is viewed on a screen without increasing the field memory,
It is an object of the present invention to provide a character data calculation device capable of smoothing the contour of a character and displaying a more legible character on the screen by reducing the step appearing in the oblique contour in the stepwise step.

[0008]

In order to achieve this object, the character data arithmetic unit of the present invention has a desired character information for a video signal output to a television monitor by an interlaced scanning system as shown in FIG. An image character data arithmetic device used in an image processing device for superimposing and displaying
First storage means for storing display character information for one horizontal line; second storage means for storing display character information for one horizontal line two lines after the one horizontal line; and two lines And a calculating means for calculating one-line display character data between two lines based on the minute display character information.

[0009]

According to the image character data arithmetic device of the present invention having the above-mentioned structure, the first storage means is such that one horizontal line of characters is displayed in the display character information for one screen stored in the field memory. Information is stored, and the second storage means stores the character information of the next successive horizontal line. The calculation means interpolates and generates data for one line between the two lines in dot units based on the character information read from the first storage means and the second storage means, and synthesizes the data with an external video signal. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of an image character data arithmetic device embodying the present invention. 4 and 5 show
It is a figure which shows how the dot information which is the minimum structural unit of a character is displayed on a TV screen.

In FIG. 2, a field memory 2 is a memory capable of storing dot information for one field. For example, character information expanded into dot data by a CPU in the apparatus is stored in an address corresponding to a display screen position. It is stored. The color of each dot is composed of three primary colors of red, green and blue. For example, if each color can have 3-bit information, 512 colors can be represented.

The interface 4 inputs a video signal (NTSC signal) from the outside and supplies the obtained external video signal 24 to the sync separation circuit 6 and the NTSC encoder 8. The sync separation circuit 6 separates a vertical sync signal and a horizontal sync signal included in the external video signal 24 into a sync signal 1
2 is output to the memory controller 10. The memory controller 10 reads the dot data as the character information from the field memory 2 based on the obtained synchronization signal 12. Further, a clock signal 16 synchronized with the video data is generated from the synchronization signal 12, and the writing / reading SW3
8 and the data calculation unit 40 and the D / A converter 18.

The write / read SW 38 controls the first line memory 34 and the second line memory 36.
The data of the (m + 1) th line is stored in the first line memory 34, and the data of the mth line is stored in the second line memory 36. These two line memories are first-in first-out memory. The data stored in the two line memories is read by the signal from the SW 38 and sent to the data calculation unit 40.

The data calculation unit 40 sequentially generates data for one line by an algorithm described later and outputs the data to the selector 50. The selector 50 determines whether the external video signal is an odd field or an even field based on the field signal 48 obtained from the sync separation circuit 6,
If it is an odd field, the digital RGB signal 32 is selected, and if it is an even field, the operation data 22 is selected and output. The D / A converter 18 converts the data input from the selector into an analog RGB signal and outputs it to the NTSC encoder 8. The NTSC encoder 8 superimposes analog RGB data on the external video signal and outputs the NTSC signal 26 to the TV monitor to obtain a composite screen.

Next, a series of operations of the image character data arithmetic unit having the above structure will be described in detail with reference to the flow chart of FIG. First, the sync separation circuit 6 outputs as a field discrimination signal 48 whether the video signal coming from the sync signal included in the external video signal 24 is an odd field or an even field (S10). In the case of odd fields, when the sync separation circuit 6 detects a vertical sync signal, the memory controller 10 which receives the vertical sync signal sends character data to the field memory 2 from the memory address corresponding to the upper left corner of the screen when the horizontal sync signal arrives. In addition, the control signal 14 for reading one dot at a time is output. The data read from the field memory 2 by the control signal 14 is output to the D / A converter 18 via the selector 50 without passing through the data operation unit 40 (S12).

On the other hand, in the case of an even field, the result calculated by the data calculator 40 is passed through the selector 50 to D /
It is output to the A converter 18 (S11). By repeating such a series of operations and repeating the data read operation for each line, the obtained analog RGB data 20 is combined with the external video signal by the NTSC encoder 8 and the display data for one field is output (S13). , (S1
4). By repeating this operation alternately with the odd field and the even field, one screen is formed.

Next, the flow chart of FIG. 8 and FIGS.
The algorithm for generating even field data will be described using. As described above, the character information read from the field memory 2 in synchronization with the external video signal is stored in the first line memory 34 as display data for one line by the clock signal output from the writing / reading SW 38. To be done. At the same time, the display data written in the first line memory 34 is read by outputting a read clock signal to the first line memory 34 and written in the second line memory 36.
The character information for one line read from the field memory 2, that is, the character information for a line continuous with the one line, starting from the next horizontal synchronization signal, is output by the write clock signal output from the write / read SW 38. One line memory 34 stores display data for one line.

When the data for two lines are gathered in this way, the write / read SW 38 sets the first line memory 3
4, the read signal is supplied to the second line memory 36, and the read character information is sent to the data calculation unit 40. The data calculation unit 40 is composed of three blocks, that is, an R data calculation 42, a G data calculation 44, and a B data calculation unit 46, in order to execute calculation for each of red, green, and blue that form character information. What must be explained in advance here is the relative relationship between the horizontal line of the external video signal 24 and the horizontal line defined in the field memory 2. That is, on the field memory, the m line and the (m + 1) line are vertically adjacent to each other,
Since the video signal is interlaced scanning as shown in FIG. 3, when the information of the field memory 2 is synthesized and displayed on the monitor 28, if the data of the m line is synthesized with the n line of the video signal 24, The data of the (m + 1) line will be combined with the (n + 2) line. Less than,
The description will be made assuming that m = n and m + 1 = n + 2.

A process of generating data by calculation when data is combined in even fields will be described with reference to the flowchart of FIG. First, it is determined whether or not there is data at the position of the horizontal position X dot of the nth line obtained from the second line memory 36 (hereinafter, described as (n, X)) (S1). If (n + 1, X) data is defined as none. On the other hand, if it is determined that there is data in S1, it is obtained from the first line memory 34 (n +
2, X-1) determines whether or not there is data (S2),
If not, the data is defined as (n + 1, X) = (n, X) (S3). On the other hand, when it is determined that there is data in S2, the same data as (n, X) is defined in (n + 1, X-0.5) as shown in FIG. 4 (S4). This makes it possible to soften the jagged edges on the left side. Furthermore, (n,
It is determined whether or not there is data in (X + 1) (S5), if there is no data, nothing is done, and if there is data, it is determined whether or not there is data in (n + 2, X) (S6). If there is no data here, nothing is done, and if there is (n + 1, X) as shown in FIG.
The same data as (n, X + 1) is defined in (+0.5) (S7).

As described above, by interpolating one line between two lines based on the data for two lines by the above method, it is possible to reduce the jaggedness seen in the outline of the character. As a result, a resolution twice as high as the actual resolution of the character data can be obtained, and the outline of the character when the character is displayed on the screen becomes smooth and easy to see. In the above embodiment, the calculation data is displayed in the even field,
The configuration may be such that the arithmetic data is displayed in the odd field and the data of the field memory is displayed in the even field. Further, if the data calculation unit 40 takes the average of the (n, X) data and the (n + 2, X) data,
It is possible to obtain pseudo double the resolution in the vertical direction. As a result, when graphic data such as a natural image is stored in the field memory, 400 lines of display can be obtained with a memory capacity of 200 lines, for example.

[0021]

As is apparent from the above description, the image character data arithmetic device of the present invention is a device constituted by a memory for one field. Also, there is an effect that the display of the character data to be combined is easy to see because it is doubled.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of the present invention.

FIG. 2 is a functional block configuration diagram of an image character data calculation device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a correspondence between a monitor screen and interlaced scanning lines.

FIG. 4 is a diagram showing a display example of dot data obtained by the present invention.

FIG. 5 is a diagram showing a display example of dot data obtained by the present invention.

FIG. 6 is an enlarged view of character data.

FIG. 7 is a flowchart showing an embodiment of the present invention.

FIG. 8 is a flowchart showing an algorithm of data calculation in the embodiment of the present invention.

FIG. 9 is a functional block configuration diagram of a character data synthesizer according to a conventional technique.

FIG. 10 is a diagram showing a dot data display example according to a conventional technique.

[Explanation of symbols]

 34 first line memory 36 second line memory 40 data operation unit

Claims (1)

[Claims] 1. A display character information for one horizontal line in an image character data arithmetic unit used for image processing for superimposing and displaying desired character information on a video signal output to a television monitor by an interlaced scanning method. A first storage means for storing the display character information, a second storage means for storing display character information for one horizontal line after two horizontal lines with respect to the one horizontal line, a first storage means and a second storage means. Image character data operation, which comprises an operation means for operating the one-line display character information between two lines of the first and second storage means based on the display character information stored in apparatus.